The present invention relates to a method of making die plates, particularly die plates used to cut and/or crease paper or cardboard.
Boxes and cartons for many products are made from heavy paper or cardboard. Machines have been developed which cut carton or box blanks from a web of heavy paper or cardboard. The blank may then be folded in an automatic folding machine or otherwise to form a box or carton.
The machines which cut the blanks utilize a pair of die plates mounted on rotatable cylinders to cut and/or crease the material as it passes through a nip defined by the two cylinders. Each die plate has lands which are raised above the surface of the rest of the die plate. Lands on one plate cooperate with those on the other plate to effect cutting. In the past cooperating lands have been made to overlap, but they do not touch each other as the rotating cylinders bring them into alignment. The lands effect "rupture cutting" of the material as it is passed through a nip defined by the cylinders. Creases may be formed in the material by locating a land on one die plate between two spaced apart lands on the cooperating die plate.
Numerous methods have been used in the past to form these die plates. Much effort has been devoted to developing a method of making die plates by which lands may be accurately located on one die plate for cooperation with lands on another die plate. Success in this effort has not been complete and inaccuracies persist as a problem. One successful method is the method disclosed in U.S. Pat. No. 3,895,947 issued to the present applicant. The known methods of making die plates are accompanied by certain drawbacks such as being expensive or laborious. For example, considerable manual labor and dexterity are required to practice the method of U.S. Pat. No. 3,895,947.